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The Cozzarelli Prize
Congratulations to the 2020 Cozzarelli Prize recipients

Please join us in congratulating the recipients of the 2020 Cozzarelli Prize! Chosen from the nearly 4,000 research articles that appeared in the journal in 2020, this year’s winners represent exceptional scientific achievement, originality, and innovation in their fields.
About the Cozzarelli Prize
The Cozzarelli Prize is awarded annually to six research teams whose PNAS articles have made outstanding contributions to their fields. Each team represents one of the six classes of the National Academy of Sciences (NAS): Physical and Mathematical Sciences; Biological Sciences; Engineering and Applied Sciences; Biomedical Sciences; Behavioral and Social Sciences; and Applied Biological, Agricultural, and Environmental Sciences.
The Cozzarelli Prize was established as the PNAS Paper of the Year Prize in 2005 and renamed in 2007 to honor former PNAS Editor-in-Chief Nicholas R. Cozzarelli (1938–2006). Elected to the NAS in 1989, Dr. Cozzarelli pioneered the study of the enzymes that control the coiling and knotting of DNA; his work underscores much of what we know about DNA synthesis. As PNAS editor-in-chief, he created the Direct Submission track, diversified the Editorial Board to include all scientific disciplines, introduced an open access publishing option, and added nonresearch content to make the journal, and science, more accessible. In honor of Dr. Cozzarelli, the award is presented to researchers that share his uncompromising scientific standards, his dedication to advancing scientific knowledge, and his enthusiasm for an “upstream swim.”
The 2020 Cozzarelli Prize will be awarded at the 158th Annual Meeting of the National Academy of Sciences in April 2021 in Washington, DC. Prize recipients receive a certificate of award, and, because this year’s meeting will be held virtually, PNAS will produce short, 2–3 minute videos about each paper. Each winning research team is featured on an episode of the PNAS Science Sessions podcast, and PNAS promotes their work to a broad scientific audience on the website and across social media channels.
Additionally, the Editorial Board has recognized six papers—one in each class—as finalists for the 2020 Cozzarelli Prize. These outstanding papers will be featured on the PNAS website and promoted across social media channels.
2020 Cozzarelli Prize recipients
Class I: Physical and Mathematical Sciences

Universal free-energy landscape produces efficient and reversible electron bifurcation
J. L. Yuly, P. Zhang, C. E. Lubner, J. W. Peters, and D. N. Beratan
Electron bifurcation is an often-reversible and efficient two-electron transfer process encountered in biological reaction networks, such as nitrogen fixation and carbon dioxide reduction. However, the physical principles that suppress energy-dissipating and short-circuiting reactions that might occur in bifurcating networks were unclear. Of the possible free-energy landscapes for reversible electron bifurcation, the authors found, efficient bifurcation emerges naturally in a generic free-energy scheme with two steep electron-transfer pathways branching from the bifurcating site. The results reveal the intrinsic properties of this free-energy landscape, illustrate how electron bifurcation can be realized with efficiency, and could guide future efforts to create synthetic electron bifurcation systems.
Class I Finalist
Evidence for aggregation-independent, PrPc-mediated Aβ cellular internalization
Alejandro R. Foley, Graham P. Roseman, Ka Chan, Amanda Smart, Thomas S. Finn, Kevin Yang, R. Scott Lokey, Glenn L. Millhauser, and Jevgenij A. Raskatov
Class II: Biological Sciences

B2 and ALU retrotransposons are self-cleaving ribozymes whose activity is enhanced by EZH2
Alfredo J. Hernandez, Athanasios Zovoilis, Catherine Cifuentes-Rojas, Lu Han, Bojan Bujisic, and Jeannie T. Lee
Ribozymes are segments of RNA that act as enzymes, but their physiological functions are often unclear. Working with the mouse genome, the authors examined B2 elements, which are short interspersed nuclear elements that produce RNA that is cleaved during interaction with the protein EZH2 and that activate genes implicated in heat stress. EZH2 is not a known nuclease enzyme, and the authors found that RNAs made from B2—as well as its human analog ALU—are self-cleaving ribozymes whose cleavage activity is accelerated in the presence of EZH2. The results suggest that B2/ALU elements, which may represent the predominant ribozyme activity in mammalian cells, can be classified as epigenetic ribozymes, which are gene expression switches that can be activated during stress.
Class II Finalist
USP7 regulates ALS-associated proteotoxicity and quality control through the NEDD4L–SMAD pathway
Tao Zhang, Goran Periz, Yu-Ning Lu, and Jiou Wang
Class III: Engineering and Applied Sciences

A scalable pipeline for designing reconfigurable organisms
Sam Kriegman, Douglas Blackiston, Michael Levin, and Josh Bongard
For biotechnological applications, living organisms offer advantages such as self-renewal and biocompatibility, compared with inanimate technologies. Using artificial intelligence, the authors developed a process for designing synthetic organisms for specified functions. Next, the authors used a cell-based construction kit and pluripotent stem cells from Xenopus frogs to create the organisms using living cells. Using this approach, the authors designed and evolved in silico structures capable of locomotion, object manipulation, object transport, and collective behavior. Fabricated cellular structures emulated not only the form but also the function of the in silico designs. The results suggest a wide array of applications, from precise drug delivery to environmental remediation.
Class III Finalist
Bioinspired underwater locomotion of light-driven liquid crystal gels
Hamed Shahsavan, Amirreza Aghakhani, Hao Zeng, Yubing Guo, Zoey S. Davidson, Arri Priimagi, and Metin Sitti
Class IV: Biomedical Sciences

HIV-1 uncoats in the nucleus near sites of integration
Ryan C. Burdick, Chenglei Li, MohamedHusen Munshi, Jonathan M. O. Rawson, Kunio Nagashima, Wei-Shau Hu, and Vinay K. Pathak
During infection, the human immunodeficiency virus (HIV-1) must disassemble the capsid coating surrounding its viral DNA before incorporating the DNA into the host genome. However, the intracellular location and timing of viral uncoating have been unclear, with previous studies suggesting uncoating in the cytoplasm and outside the nucleus. The authors labeled the HIV-1 capsid protein and identified infectious virions, finding that viral cores enter the nucleus intact or nearly intact, and that uncoating occurs near the genomic integration site, within 1.5 hours of integration. The findings provide fundamental insights into HIV-1 behavior upon entering human cells and suggest that maintaining an intact core until shortly before integration may aid efficient viral replication and evasion of cellular immune responses.
Class IV Finalist
Uncoupling DNA damage from chromatin damage to detoxify doxorubicin
Xiaohang Qiao, Sabina Y. van der Zanden, Dennis P. A. Wander, Daniel M. Borràs, Ji-Ying Song, Xiaoyang Li, Suzanne van Duikeren, Noortje van Gils, Arjo Rutten, Tessa van Herwaarden, Olaf van Tellingen, Elisa Giacomelli, Milena Bellin, Valeria Orlova, Leon G. J. Tertoolen, Sophie Gerhardt, Jimmy J. Akkermans, Jeroen M. Bakker, Charlotte L. Zuur, Baoxu Pang, Anke M. Smits, Christine L. Mummery, Linda Smit, Ramon Arens, Junmin Li, Hermen S. Overkleeft, and Jacques Neefjes
Class V: Behavioral and Social Sciences

Image credit: Shutterstock/Mongkolchon Akesin.
Physician–patient racial concordance and disparities in birthing mortality for newborns
Brad N. Greenwood, Rachel R. Hardeman, Laura Huang, and Aaron Sojourner
Studies showing racial disparities in infant mortality find that Black newborns die at three times the rate of White newborns; other studies have found that underrepresented minorities may benefit from racial concordance between patient and physician. The authors examined records of 1.8 million hospital births in Florida between 1992 and 2015 and found that when Black newborns received care from Black physicians, the mortality disparity with White newborns was reduced by half. Racial concordance did not significantly improve mortality outcomes among Black birthing mothers. The findings suggest that the benefits of patient–physician racial concordance may be enhanced in challenging birth scenarios and in hospitals that deliver high numbers of Black babies.
Class V Finalist
Cross-level sociodemographic homogeneity alters individual risk for completed suicide
Bernice A. Pescosolido, Byungkyu Lee, and Karen Kafadar
Class VI: Applied Biological, Agricultural, and Environmental Sciences

Michael A. Gil, Marissa L. Baskett, Stephan B. Munch, and Andrew M. Hein
Human-driven environmental changes can alter animal behavior, which, in turn, can affect species demographics. However, behavioral patterns are often not considered in population models designed to evaluate ecosystem responses to environmental change. The authors used extensive data on foraging behavior of herbivorous fish in a coral reef, combined with empirical demographic estimates, to develop a coupled behavioral–demographic ecosystem model. Inclusion of behavioral feedbacks revealed that the ecosystem was susceptible not only to the magnitude of changes in fishing pressure but also to the pace of change. The findings suggest that rapid changes, such as quickly increasing fishing to a given level, can collapse an ecosystem that would persist under more gradual change.
Class VI Finalist
Nutrient dilution and climate cycles underlie declines in a dominant insect herbivore
Ellen A. R. Welti, Karl A. Roeder, Kirsten M. de Beurs, Anthony Joern, and Michael Kaspari
2019 Cozzarelli Prize recipients
Class I: Physical and Mathematical Sciences
Daniel R. Moberg, Daniel Becker, Christoph W. Dierking, Florian Zurheide, Bernhard Bandow, Udo Buck, Arpa Hudait, Valeria Molinero, Francesco Paesani, and Thomas Zeuch
A commentary accompanying this article is available.

What is the minimum number of water molecules needed to form a stable ice crystal? To answer this question, Moberg et al. used infrared spectroscopic measurements of slow-cooled water droplets and molecular dynamics simulations. The authors identified the existence of ice in clusters of as few as 90 water molecules. The authors further determined that in clusters of fewer than 150 molecules, the equilibrium between ice and liquid occurs through oscillation of the clusters between crystalline and liquid phases. The results provide insight into the behavior of water under nanoscale confinement, which may occur in proteins and other materials.
Class II: Biological Sciences
Mosaic origin of the eukaryotic kinetochore
Eelco C. Tromer, Jolien J. E. van Hooff, Geert J. P. L. Kops, and Berend Snel
A commentary accompanying this article is available.

When eukaryotic cells evolved from prokaryotic ancestors, they vastly increased in complexity. How many of the typical eukaryotic features emerged during this process remains unclear. Tromer, van Hooff, et al. reconstructed the origin of one such feature, the kinetochore, a large proteinaceous structure that drives separation of chromosomes during cell division. The authors found that the proteins that make up the kinetochore are of mosaic origin: Some have relatives in different eukaryotic or prokaryotic cellular processes, whereas others are unique to the kinetochore. Nevertheless, many kinetochore proteins share part of their evolutionary trajectories, arising from ancient gene duplications within the kinetochore. The results suggest that the kinetochore originated by recruiting proteins globally and expanded by duplicating them locally, characterizing one of the modes by which key eukaryotic systems evolved.
Class III: Engineering and Applied Sciences
Mechanics unlocks the morphogenetic puzzle of interlocking bivalved shells
Derek E. Moulton, Alain Goriely, and Régis Chirat

Two groups of animals—brachiopods and bivalve mollusks—sport interlocking shells that help guard against predators and environmental perturbations. Each group is thought to have independently evolved bipartite shells more than 540 million years ago from a common ancestor lacking shells, and the two halves of each shell are secreted by distinct lobes of a membranous organ called the mantle. Moulton et al. used a mathematical model of shell growth to determine how the shell valves interlock tidily despite being formed separately. Seamless interlocking, the authors report, is a consequence of the geometry and physics of shell growth: Mechanical instability arising from the interaction of the soft mantle with the rigid shell edge and from the interaction between the mantle lobes results in a perfectly interlocking pattern. Moreover, the findings explain how fine-tuning the shell growth process produces the striking diversity of forms seen in shells.
Class IV: Biomedical Sciences
Widespread soil bacterium that oxidizes atmospheric methane
Alexander T. Tveit, Anne Grethe Hestnes, Serina L. Robinson, Arno Schintlmeister, Svetlana N. Dedysh, Nico Jehmlich, Martin von Bergen, Craig Herbold, Michael Wagner, Andreas Richter, and Mette M. Svenning

Atmospheric methane is a major contributor to global warming. Methane-oxidizing bacteria are an important biological sink for atmospheric methane, but no pure cultures of such microbes have been available. Tveit, Hestnes, et al. isolated a pure culture of a methane-oxidizing soil bacterium that can grow on air. The strain, which the authors named Methylocapsa gorgona MG08, oxidizes methane at atmospheric concentrations for use as a carbon and energy source. The strain is also capable of using carbon dioxide, carbon monoxide, dinitrogen, dioxygen, and hydrogen for energy conservation or biomass synthesis. The findings suggest that some microbes can satisfy their needs for energy, carbon, and nitrogen by relying solely on air.
Class V: Behavioral and Social Sciences
Clark Spencer Larsen, Christopher J. Knüsel, Scott D. Haddow, Marin A. Pilloud, Marco Milella, Joshua W. Sadvari, Jessica Pearson, Christopher B. Ruff, Evan M. Garofalo, Emmy Bocaege, Barbara J. Betz, Irene Dori, and Bonnie Glencross
A commentary accompanying this article is available.

The human transition from foraging to farming began 10,000–11,000 years ago in Southwest Asia. To determine the impact of the transition on human lifestyle, health, and culture, Larsen et al. conducted a bioarchaeological investigation at Çatalhöyük (7100–5950 cal BCE), a large Neolithic site in south-central Turkey that was continuously inhabited for 1,150 years. Building on earlier investigations, the authors analyzed the influence of the environment, diet, and living circumstances on human health and well-being at this early farming settlement. The authors found that the transition to farming led to higher birth rates, which in turn led to crowded living conditions. Such conditions contributed to increased labor demands, risk of interpersonal violence, and exposure to disease, presaging similar changes in living conditions in settlements elsewhere. The study provides rich insights into human lifestyle changes wrought by early agriculture.
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Economics of the disintegration of the Greenland ice sheet
William Nordhaus
A commentary accompanying this article is available.

Concerns about impacts on large-scale earth systems have become pertinent to the scientific analysis of climate change. While the impacts are likely to be significant, there has been little work integrating the geophysical and economic aspects of the potential disintegration of the Greenland ice sheet (GIS). Nordhaus developed a model that integrated the economics and geophysics of the GIS to investigate melt paths that would occur under different climate policies. Weak climate policies would lead to ice-sheet melting beyond a threshold known as the Robinson upper tipping point, after which rebuilding is extremely slow even if warming reverses. Conversely, strong climate policies would stop GIS disintegration before melting reaches critical tipping points. The author notes that adding the damages from GIS disintegration contributes less than 5% to the social cost of carbon, or the price of emissions in a market context, because the slow melt rate puts damages into the distant future.
2018 Cozzarelli Prize recipients
2018 Cozzarelli Prize recipients and guests. From left to right: Christine M. Dunham, Class II; Eric Boilard, Class IV; Tommaso Bellini, Class III; Robert J. Orth, Class VI; Isabelle Cozzarelli; Noel A. Clark, Class III; Linda Cozzarelli; Simon DeDeo, Class V; Cathy Cozzarelli; Alexander T. J. Barron, Class V; Alexey A. Melnikov, Class I; Hendrik Poulsen Nautrup, Class I; Hans J. Briegel, Class I; Jonathan S. Lefcheck, Class VI.
Class I: Physical and Mathematical Sciences
Active learning machine learns to create new quantum experiments
Alexey A. Melnikov, Hendrik Poulsen Nautrup, Mario Krenn, Vedran Dunjko, Markus Tiersch, Anton Zeilinger, and Hans J. Briegel

Modern experiments in quantum physics have advanced researchers’ understanding of several fundamental concepts of quantum theory. However, further advances in quantum physics are likely to require complex experiments that are challenging to design and potentially counterintuitive. Melnikov, Poulsen Nautrup, et al. developed an artificial intelligence system capable of designing experiments for producing complex entangled photon states, which are difficult to realize experimentally. The system learned to design the desired experiments more efficiently than previous approaches, discovering nonstandard experimental techniques in the process. The work expands the possibilities for the role of machines in scientific research.
Listen to an interview with Hans J. Briegel and Hendrik Poulsen Nautrup
Class II: Biological Sciences
Mechanism of tRNA-mediated +1 ribosomal frameshifting
Samuel Hong, S. Sunita, Tatsuya Maehigashi, Eric D. Hoffer, Jack A. Dunkle, and Christine M. Dunham
A commentary accompanying this article is available.

During protein synthesis in living cells, transfer RNA (tRNA) molecules translate the genetic code embodied in messenger RNA (mRNA), which is derived from genomic DNA, into the linear sequence of amino acids found in protein chains. The fidelity of protein translation depends on the ability of tRNA to correctly read triplet nucleotide codons on mRNA, which is bound to ribosomes, cellular protein synthesizing machines. Certain tRNAs, however, can shift out of frame while reading ribosome-bound mRNAs, enabling the translation of four-nucleotide codons, a property used in biotechnology to incorporate unnatural amino acids into proteins for novel functions. Using X-ray crystallography of tRNA, mRNA, and ribosomes, Hong, Sunita, et al. showed that conformational changes in tRNA at a pair of ribosomal sites help release the ribosome’s grip on mRNA and facilitate such frameshifting. The findings illuminate the fine-grained mechanics of protein translation and could accelerate the rational design of novel proteins for vaccine and drug development.
Class III: Engineering and Applied Sciences
Backbone-free duplex-stacked monomer nucleic acids exhibiting Watson–Crick selectivity
Gregory P. Smith, Tommaso P. Fraccia, Marco Todisco, Giuliano Zanchetta, Chenhui Zhu, Emily Hayden, Tommaso Bellini, and Noel A. Clark
A commentary accompanying this article is available.

Tommaso Bellini and Noel A. Clark
How the distinctive double-helical structure of DNA originated remains an enduring puzzle. Smith, Fraccia, et al. found that nucleotides, the monomer building blocks of nucleic acid polymers, spontaneously adopt a liquid crystalline state at low temperature and high concentration, in which the nucleotides form Watson–Crick-style base pairs that stack on top of each other. The resulting structure is analogous to the DNA double helix, albeit without the phosphate backbone, and could facilitate the polymerization of nucleotides into nucleic acid chains. The findings lend potential insights into the prebiotic emergence of nucleic acids.
Listen to an interview with Tommaso Bellini and Noel A. Clark
Class IV: Biomedical Sciences
Nathalie Cloutier, Isabelle Allaeys, Genevieve Marcoux, Kellie R. Machlus, Benoit Mailhot, Anne Zufferey, Tania Levesque, Yann Becker, Nicolas Tessandier, Imene Melki, Huiying Zhi, Guy Poirier, Matthew T. Rondina, Joseph E. Italiano, Louis Flamand, Steven E. McKenzie, Francine Cote, Bernhard Nieswandt, Waliul I. Khan, Matthew J. Flick, Peter J. Newman, Steve Lacroix, Paul R. Fortin, and Eric Boilard

Platelets are primarily known for blood clotting, but they also play a role in immunity. Cloutier, Allaeys, et al. analyzed platelet activation in mice in response to systemic immune complexes (ICs). The authors examined transgenic mice expressing FcγRIIA, which are IC receptors, on platelets. When injected with platelet-activating ICs, FcγRIIA mice lost consciousness and suffered from systemic shock, which was dependent on serotonin release from platelet granules. Activated platelets returned to circulation after degranulation and sequestered in the brain and lungs. However, mice lacking platelet serotonin were almost completely shock-resistant and did not release serotonin when exposed to ICs. Thus, platelets may mediate shock in conditions such as anaphylaxis and sepsis, and platelet-derived serotonin might be a key shock mediator.
Listen to an interview with Eric Boilard
Class V: Behavioral and Social Sciences
Individuals, institutions, and innovation in the debates of the French Revolution
Alexander T. J. Barron, Jenny Huang, Rebecca L. Spang, and Simon DeDeo

The French Revolution set an example for future democracies. To determine how speaking patterns during the Revolution were adopted or ignored, Barron et al. analyzed 44,913 speeches from the Revolution’s first parliament—the National Constitution Assembly (NCA)—from July 1789 to September 1791. Compared with conservatives, radicals more frequently discussed short-lived novel concepts. Whereas conservatives discussed traditional ideas with long-lived resonance, the NCA’s tendency to discuss novel concepts was influenced by radicals who frequently proposed new ideas that were continuously debated. The study provides insight into why radicals such as Maximilien Robespierre and Jérôme Pétion de Villeneuve were among the Revolution’s most influential figures. It also reveals the emergence of committees as political forces, marking a shift in decision-making from large-scale public debates to private deliberations of small cohorts.
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Long-term nutrient reductions lead to the unprecedented recovery of a temperate coastal region
Jonathan S. Lefcheck, Robert J. Orth, William C. Dennison, David J. Wilcox, Rebecca R. Murphy, Jennifer Keisman, Cassie Gurbisz, Michael Hannam, J. Brooke Landry, Kenneth A. Moore, Christopher J. Patrick, Jeremy Testa, Donald E. Weller, and Richard A. Batiuk
Nutrients and Chesapeake Bay Recovery on the PNAS Science Sessions podcast
Jonathan Lefcheck and Robert Orth discuss nutrient pollution and recovery in the Chesapeake Bay.
A commentary accompanying this article is available.

Using aerial surveys, biogeochemical data, and watershed and historical land use information, Lefcheck et al. analyzed the relationship between nutrient pollution and submerged aquatic vegetation (SAV) in the Chesapeake Bay, United States, from 1984 to 2014. The analysis revealed that reduced nitrogen and phosphorus inputs to the bay increased SAV cover, by both increasing water clarity and reducing algal blooms. The results suggest that reducing nutrient pollution and conserving or restoring species diversity can lead to long-term ecosystem recovery in the Chesapeake Bay.
Listen to an interview with Jonathan S. Lefcheck and Robert J. Orth
2017 Cozzarelli Prize Recipients
Class I: Physical and Mathematical Sciences
Origin of the RNA world: The fate of nucleobases in warm little ponds
Ben K. D. Pearce, Ralph E. Pudritz, Dmitry A. Semenov, and Thomas K. Henning
A commentary accompanying this article is available.
Listen to an interview with Ben K. D. Pearce
Class II: Biological Sciences
Linlin Zhang, Anyi Mazo-Vargas, and Robert D. Reed
Class III: Engineering and Applied Sciences
Nondestructive nanostraw intracellular sampling for longitudinal cell monitoring
Yuhong Cao, Martin Hjort, Haodong Chen, Fikri Birey, Sergio A. Leal-Ortiz, Crystal M. Han, Juan G. Santiago, Sergiu P. Paşca, Joseph C. Wu, and Nicholas A. Melosh
Class IV: Biomedical Sciences
Maridel A. Fredericksen, Yizhe Zhang, Missy L. Hazen, Raquel G. Loreto, Colleen A. Mangold, Danny Z. Chen, and David P. Hughes
Listen to an interview with David P. Hughes
Class V: Behavioral and Social Sciences
Language from police body camera footage shows racial disparities in officer respect
Rob Voigt, Nicholas P. Camp, Vinodkumar Prabhakaran, William L. Hamilton, Rebecca C. Hetey, Camilla M. Griffiths, David Jurgens, Dan Jurafsky, and Jennifer L. Eberhardt
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Elizabeth Trembath-Reichert, Yuki Morono, Akira Ijiri, Tatsuhiko Hoshino, Katherine S. Dawson, Fumio Inagaki, and Victoria J. Orphan
A commentary accompanying this article is available.
2016 Cozzarelli Prize Recipients
Class I: Physical and Mathematical Sciences
Quantum violation of the pigeonhole principle and the nature of quantum correlations
Yakir Aharonov, Fabrizio Colombo, Sandu Popescu, Irene Sabadini, Daniele C. Struppa, and Jeff Tollaksen
Listen to an interview with Sandu Popescu and Jeff Tollaksen
Class II: Biological Sciences
Complete in vitro generation of fertile oocytes from mouse primordial germ cells
Kanako Morohaku, Ren Tanimoto, Keisuke Sasaki, Ryouka Kawahara-Miki, Tomohiro Kono, Katsuhiko Hayashi, Yuji Hirao, and Yayoi Obata
A commentary accompanying this article is available.
Listen to an interview with Yayoi Obata
Class III: Engineering and Applied Sciences
Biqin Dong, Luay M. Almassalha, Yolanda Stypula-Cyrus, Ben E. Urban, John E. Chandler, The-Quyen Nguyen, Cheng Sun, Hao F. Zhang, and Vadim Backman
Listen to an interview with Vadim Backman
Class IV: Biomedical Sciences
George Hoppe, Suzy Yoon, Banu Gopalan, Alexandria R. Savage, Rebecca Brown, Kelsey Case, Amit Vasanji, E. Ricky Chan, Randi B. Silver, and Jonathan E. Sears
Listen to an interview with Jonathan Sears
Class V: Behavioral and Social Sciences
The emergence of longevous populations
Fernando Colchero, Roland Rau, Owen R. Jones, Julia A. Barthold, Dalia A. Conde, Adam Lenart, Laszlo Nemeth, Alexander Scheuerlein, Jonas Schoeley, Catalina Torres, Virginia Zarulli, Jeanne Altmann, Diane K. Brockman, Anne M. Bronikowski, Linda M. Fedigan, Anne E. Pusey, Tara S. Stoinski, Karen B. Strier, Annette Baudisch, Susan C. Alberts, and James W. Vaupel
Listen to an interview with Fernando Colchero, Roland Rau, and Susan Alberts
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Timing and causes of mid-Holocene mammoth extinction on St. Paul Island, Alaska
Russell W. Graham, Soumaya Belmecheri, Kyungcheol Choy, Brendan J. Culleton, Lauren J. Davies, Duane Froese, Peter D. Heintzman, Carrie Hritz, Joshua D. Kapp, Lee A. Newsom, Ruth Rawcliffe, Émilie Saulnier-Talbot, Beth Shapiro, Yue Wang, John W. Williams, and Matthew J. Wooller
Listen to an interview with Russell Graham
2015 Cozzarelli Prize Recipients
Class I: Physical and Mathematical Sciences
Mimicking the magnetic properties of rare earth elements using superatoms
Shi-Bo Cheng, Cuneyt Berkdemir, and A. W. Castleman Jr.
Listen to an interview with Will Castleman and Cuneyt Berkdemir
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Class II: Biological Sciences
Maternal intestinal HIF-2α is necessary for sensing iron demands of lactation in mice
Sadeesh K. Ramakrishnan, Erik R. Anderson, Angelical Martin, Brook Centofanti, and Yatrik M. Shah
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Class III: Engineering and Applied Sciences
Origami tubes assembled into stiff, yet reconfigurable structures and metamaterials
Evgueni T. Filipov, Tomohiro Tachi, and Glaucio H. Paulino
A commentary accompanying this article is available.
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Class IV: Biomedical Sciences
Evidence for α-synuclein prions causing multiple system atrophy in humans with parkinsonism
Stanley B. Prusiner, Amanda L. Woerman, Daniel A. Mordes, Joel C. Watts, Ryan Rampersaud, David B. Berry, Smita Patel, Abby Oehler, Jennifer K. Lowe, Stephanie N. Kravitz, Daniel H. Geschwind, David V. Glidden, Glenda M. Halliday, Lefkos T. Middleton, Steve M. Gentleman, Lea T. Grinberg, and Kurt Giles
A commentary accompanying this article is available.
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Class V: Behavioral and Social Sciences
Rising morbidity and mortality in midlife among white non-Hispanic Americans in the 21st century
Anne Case and Angus Deaton
A commentary accompanying this article is available.
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Class VI: Applied Biological, Agricultural, and Environmental Sciences
Mark Z. Jacobson, Mark A. Delucchi, Mary A. Cameron, and Bethany A. Frew
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2014 Cozzarelli Prize Recipients
Class I: Physical and Mathematical Sciences
High-precision timeline for Earth’s most severe extinction
Seth D. Burgess, Samuel Bowring, and Shu-zhong Shen
A commentary accompanying this article is available.
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Class II: Biological Sciences
A propagating ATPase gradient drives transport of surface-confined cellular cargo
Anthony G. Vecchiarelli, Keir C. Neuman, and Kiyoshi Mizuuchi
A commentary accompanying this article is available.
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Class III: Engineering and Applied Sciences
Sangwoo Lee, Chris Leighton and Frank S. Bates
A commentary accompanying this article is available.
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Class IV: Biomedical Sciences
Transfer of noncoding DNA drives regulatory rewiring in bacteria
Yaara Oren, Mark B. Smith, Nathan I. Johns, Millie Kaplan Zeevi, Dvora Biran, Eliora Z. Ron, Jukka Corander, Harris H. Wang, Eric J. Alm, and Tal Pupko
A commentary accompanying this article is available.
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Class V: Behavioral and Social Sciences
Neural and cognitive characteristics of extraordinary altruists
Abigail A. Marsh, Sarah A. Stoycos, Kristin M. Brethel-Haurwitz, Paul Robinson, John W. VanMeter, and Elise M. Cardinale
A commentary accompanying this article is available.
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Class VI: Applied Biological, Agricultural, and Environmental Sciences
China's international trade and air pollution in the United States
Jintai Lin, Da Pan, Steven J. Davis, Qiang Zhang, Kebin He, Can Wang, David G. Streets, Donald J. Wuebbles, and Dabo Guan
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2013 Cozzarelli Prize Recipients
Class I: Physical and Mathematical Sciences
The prevalence of Earth-size planets orbiting Sun-like stars
Erik A. Petigura, Andrew W. Howard, and Geoffrey W. Marcy
Listen to an interview with Erik Petigura and Geoffrey Marcy
Class II: Biological Sciences
Satoshi Kojima, Mimi H. Kao, and Allison J. Doupe
Listen to an interview with Mimi Kao and Allison Doupe
Class III: Engineering and Applied Sciences
Gas production in the Barnett Shale obeys a simple scaling theory
Tad W. Patzek, Frank Male, and Michael Marder
A commentary accompanying this article is available.
Listen to an interview with Tad Patzek
Class IV: Biomedical Sciences
Human placental trophoblasts confer viral resistance to recipient cells
Elizabeth Delorme-Axford, Rogier B. Donker, Jean-Francois Mouillet, Tianjiao Chu, Avraham Bayer, Yingshi Ouyang, Tianyi Wang, Donna B. Stolz, Saumendra N. Sarkar, Adrian E. Morelli, Yoel Sadovsky, and Carolyn B. Coyne
Listen to an interview with Yoel Sadovsky and Carolyn Coyne
Class V: Behavioral and Social Sciences
Caroline Roullier, Laure Benoit, Doyle B. McKey, and Vincent Lebot
A commentary accompanying this article is available.
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Class VI: Applied Biological, Agricultural, and Environmental Sciences
Gennaro Di Prisco, Valeria Cavaliere, Desiderato Annoscia, Paola Varricchio, Emilio Caprio, Francesco Nazzi, Giuseppe Gargiulo, and Francesco Pennacchio
Listen to an interview with Francesco Pennacchio
2012 Cozzarelli Prize Recipients
Class I: Physical and Mathematical Sciences
Water, plants, and early human habitats in eastern Africa
Clayton R. Magill, Gail M. Ashley, and Katherine H. Freeman
A commentary accompanying this article is available.
Listen to an interview with Clayton R. Magill and Katherine H. Freeman
Class II: Biological Sciences
Paloma T. Gonzalez-Bellido, Hanchuan Peng, Jinzhu Yang, Apostolos P. Georgopoulos, and Robert M. Olberg
A commentary accompanying this article is available.
Listen to an interview with Paloma Gonzalez-Bellido, Hanchuan Peng, and Apostolos Georgopoulos
Class III: Engineering and Applied Sciences
Point process modelling of the Afghan War Diary
Andrew Zammit-Mangion, Michael Dewar, Visakan Kadirkamanathan, and Guido Sanguinetti
Class IV: Biomedical Sciences
Xiaojun Lian, Cheston Hsiao, Gisela Wilson, Kexian Zhu, Laurie B. Hazeltine, Samira M. Azarin, Kunil K. Raval, Jianhua Zhang, Timothy J. Kamp, and Sean P. Palecek
Listen to an interview with Sean Palecek and Xiaojun Lian
Class V: Behavioral and Social Sciences
Evolution of music by public choice
Robert M. MacCallum, Matthias Mauch, Austin Burt, and Armand M. Leroi
A commentary accompanying this article is available.
Listen to an interview with Bob MacCallum
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Arabidopsis synchronizes jasmonate-mediated defense with insect circadian behavior
Danielle Goodspeed, E. Wassim Chehab, Amelia Min-Venditti, Janet Braam, and Michael F. Covington
A commentary accompanying this article is available.
Listen to an interview with Janet Braam and E. Wassim Chehab
2011 Cozzarelli Prize Recipients
Class I: Physical and Mathematical Sciences
Microaerobic steroid biosynthesis and the molecular fossil record of Archean life
Jacob R. Waldbauer, Dianne K. Newman, and Roger E. Summons
Listen to an interview with Jacob Waldbauer
Class II: Biological Sciences
Przemek M. Krawczyk, Berina Eppink, Jeroen Essers, Jan Stap, Hans Rodermond, Hanny Odijk, Alex Zelensky, Chris van Bree, Lukas J. Stalpers, Marrije R. Buist, Thomas Soullié, Joost Rens, Hence J. M. Verhagen, Mark J. O'Connor, Nicolaas A. P. Franken, Timo L. M. ten Hagen, Roland Kanaar, and Jacob A. Aten
A commentary accompanying this article is available.
Listen to an interview with Roland Kanaar
Class III: Engineering and Applied Sciences
The Voronoi Implicit Interface Method for computing multiphase physics
Robert I. Saye and James A. Sethian
Listen to an interview with Robert Saye and James Sethian
Class IV: Biomedical Sciences
Erica S. Machlin, Peter Sarnow, and Selena M. Sagan
A commentary accompanying this article is available.
Listen to an interview with Erica Machlin Cox and Selena Sagan
Class V: Behavioral and Social Sciences
The long shadow cast by childhood physical and mental problems on adult life
Alissa Goodman, Robert Joyce, and James P. Smith
Listen to an interview with James Smith
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Conditions associated with protected area success in conservation and poverty reduction
Paul J. Ferraro, Merlin M. Hanauer, and Katharine R. E. Sims
Listen to an interview with Merlin Hanauer
2010 Cozzarelli Prize Recipients
The 2010 Cozzarelli prize winners were honored at the PNAS Editorial Board Meeting on May 1, 2011, in National Harbor, Maryland (from left to right): Liza R. Moscovice, Won-Yong Song, Jiyoung Park, Jasmine T. Perez, Benjamin R. tenOever, Edward Barry, Zvonimir Dogic, Sheng-Li Cai, Angela Alexander, Cheryl Lyn Walker, Robina Shaheen, and Gerardo Dominguez.
Class I: Physical and Mathematical Sciences
R. Shaheen, A. Abramian, J. Horn, G. Dominguez, R. Sullivan, and Mark H. Thiemens
Class II: Biological Sciences
ATM signals to TSC2 in the cytoplasm to regulate mTORC1 in response to ROS
Angela Alexander, Sheng-Li Cai, Jinhee Kim, Adrian Nanez, Mustafa Sahin, Kirsteen H. MacLean, Ken Inoki, Kun-Liang Guan, Jianjun Shen, Maria D. Person, Donna Kusewitt, Gordon B. Mills, Michael B. Kastan, and Cheryl Lyn Walker
Class III: Engineering and Applied Sciences
Entropy driven self-assembly of nonamphiphilic colloidal membranes
Edward Barry and Zvonimir Dogic
Class IV: Biomedical Sciences
Influenza A virus-generated small RNAs regulate the switch from transcription to replication
Jasmine T. Perez, Andrew Varble, Ravi Sachidanandam, Ivan Zlatev, Muthiah Manoharan, Adolfo García-Sastre, and Benjamin R. tenOever
A commentary accompanying this article is available.
Class V: Behavioral and Social Sciences
Contingent cooperation between wild female baboons
Dorothy L. Cheney, Liza R. Moscovice, Marlies Heesen, Roger Mundry, and Robert M. Seyfarth
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Arsenic tolerance in Arabidopsis is mediated by two ABCC-type phytochelatin transporters
Won-Yong Song, Jiyoung Park, David G. Mendoza-Cózatl, Marianne Suter-Grotemeyer, Donghwan Shim, Stefan Hörtensteiner, Markus Geisler, Barbara Weder, Philip A. Rea, Doris Rentsch, Julian I. Schroeder, Youngsook Lee, and Enrico Martinoia
A commentary accompanying this article is available.
2009 Cozzarelli Prize Recipients
The 2009 Cozzarelli prize winners were honored at the PNAS Editorial Board Meeting on April 25, 2010, in National Harbor, Maryland (from left to right): Christian Degen, Dan Rugar, Vera Gorbunova, Andrei Seluanov, Michael Köttgen, Owen Woodward, Mary Helen Immordino-Yang, Lennart Balk, Per-Åke Hägerroth, John Dore, and David Karl.
Class I: Physical and Mathematical Sciences
Physical and biogeochemical modulation of ocean acidification in the central North Pacific
John E. Dore, Roger Lukas, Daniel W. Sadler, Matthew J. Church, and David M. Karl
A commentary accompanying this article is available.
Class II: Biological Sciences
Identification of a urate transporter, ABCG2, with a common functional polymorphism causing gout
Owen M. Woodward, Anna Köttgen, Josef Coresh, Eric Boerwinkle, William B. Guggino, and Michael Köttgen
Class III: Engineering and Applied Sciences
Nanoscale magnetic resonance imaging
C. L. Degen, M. Poggio, H. J. Mamin, C. T. Rettner, and D. Rugar
A commentary accompanying this article is available.
Class IV: Biomedical Sciences
Hypersensitivity to contact inhibition provides a clue to cancer resistance of naked mole-rat
Andrei Seluanov, Christopher Hine, Jorge Azpurua, Marina Feigenson, Michael Bozzella, Zhiyong Mao, Kenneth C. Catania, and Vera Gorbunova
A commentary accompanying this article is available.
Class V: Behavioral and Social Sciences
Neural correlates of admiration and compassion
Mary Helen Immordino-Yang, Andrea McColl, Hanna Damasio, and Antonio Damasio
A commentary accompanying this article is available.
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Wild birds of declining European species are dying from a thiamine deficiency syndrome
Lennart Balk, Per-Åke Hägerroth, Gun Åkerman, Marsha Hanson, Ulla Tjärnlund, Tomas Hansson, Gunnar Thor Hallgrimsson, Yngve Zebühr, Dag Broman, Torsten Mörner, and Henrik Sundberg
2008 Cozzarelli Prize Recipients
The 2008 Cozzarelli prize winners were honored at the PNAS Editorial Board Meeting on April 26, 2009, in Washington, DC (from left to right): Katia Koelle, Yoshiro Nagao, Raymond Jeanloz, Marius Wernig, Daniel H. Kim, John J. Rossi, Karen McComb, Leanne Proops, and Albert-Laszlo Barabási.
Class I: Physical and Mathematical Sciences
Fluid helium at conditions of giant planetary interiors
Lars Stixrude and Raymond Jeanloz
A commentary accompanying this article is available.
Class II: Biological Sciences
MicroRNA-directed transcriptional gene silencing in mammalian cells
Daniel H. Kim, Pål Sætrom, Ola Snøve, Jr., and John J. Rossi
Class III: Engineering and Applied Sciences
The implications of human metabolic network topology for disease comorbidity
D.-S. Lee, J. Park, K. A. Kay, N. A. Christakis, Z. N. Oltvai, and A.-L. Barabási
A commentary accompanying this article is available.
Class IV: Biomedical Sciences
Marius Wernig, Jian-Ping Zhao, Jan Pruszak, Eva Hedlund, Dongdong Fu, Frank Soldner, Vania Broccoli, Martha Constantine-Paton, Ole Isacson, and Rudolf Jaenisch
Class V: Behavioral and Social Sciences
Cross-modal individual recognition in domestic horses (Equus caballus)
Leanne Proops, Karen McComb, and David Reby
A commentary accompanying this article is available.
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Decreases in dengue transmission may act to increase the incidence of dengue hemorrhagic fever
Yoshiro Nagao and Katia Koelle
2007 Cozzarelli Prize Recipients
The 2007 Cozzarelli prize winners were honored at the PNAS Editorial Board Meeting on April 27, 2008, in Washington, DC (from left to right): Serguei N. Skatchkov, Andreas Reichenbach, Tommy Cedervall, R. Adriana Hernandez-Aguilar, Jim Moore, Iseult Lynch, Kenneth A. Dawson, Monica Olvera de la Cruz, Graziano Vernizzi, Brian Spencer, Kristian Franze, and Sandra Díaz.
Class I: Physical and Mathematical Sciences
Tommy Cedervall, Iseult Lynch, Stina Lindman, Tord Berggrd, Eva Thulin, Hanna Nilsson, Kenneth A. Dawson, and Sara Linse
A commentary accompanying this article is available.
Class II: Biological Sciences
Müller cells are living optical fibers in the vertebrate retina
Kristian Franze, Jens Grosche, Serguei N. Skatchkov, Stefan Schinkinger, Christian Foja, Detlev Schild, Ortrud Uckermann, Kort Travis, Andreas Reichenbach, and Jochen Guck
Class III: Engineering and Applied Sciences
Faceting ionic shells into icosahedra via electrostatics
Graziano Vernizzi and Monica Olvera de la Cruz
Class IV: Biomedical Sciences
Targeted delivery of proteins across the blood-brain barrier
Brian J. Spencer and Inder M. Verma
A commentary accompanying this article is available.
Class V: Behavioral and Social Sciences
Savanna chimpanzees use tools to harvest the underground storage organs of plants
R. Adriana Hernandez-Aguilar, Jim Moore, and Travis Rayne Pickering
A commentary accompanying this article is available.
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Incorporating plant functional diversity effects in ecosystem service assessments
Sandra Díaz, Sandra Lavorel, Francesco de Bello, Fabien Quétier, Karl Grigulis, and T. Matthew Robson
This article was cited in the PNAS Land Change Science Special Feature.
2006 Cozzarelli Prize Recipients
The 2006 Cozzarelli prize winners were honored at the PNAS Editorial Board Meeting on April 29, 2007, in Washington, DC (from left to right): Francesco Mallamace, Sow-Hsin Chen, Pat Levitt, Christian J. Kastrup, Stefan W. Hell, Gerald Donnert, Jeffrey R. Vincent, and Maximilian Auffhammer.
Class I: Physical and Mathematical Sciences
Christian J. Kastrup, Matthew K. Runyon, Feng Shen, and Rustem F. Ismagilov
A commentary accompanying this article is available.
Class II: Biological Sciences
Macromolecular-scale resolution in biological fluorescence microscopy
Gerald Donnert, Jan Keller, Rebecca Medda, M. Alexandra Andrei, Silvio O. Rizzoli, Reinhard Lührmann, Reinhard Jahn, Christian Eggeling, and Stefan W. Hell
Class III: Engineering and Applied Sciences
The violation of the Stokes-Einstein relation in supercooled water
Sow-Hsin Chen, Francesco Mallamace, Chung-Yuan Mou, Matteo Broccio, Carmelo Corsaro, Antonio Faraone, and Li Liu
A commentary accompanying this article is available.
Class IV: Biomedical Sciences
A genetic variant that disrupts MET transcription is associated with autism
Daniel B. Campbell, James S. Sutcliffe, Philip J. Ebert, Roberto Militerni, Carmela Bravaccio, Simona Trillo, Maurizio Elia, Cindy Schneider, Raun Melmed, Roberto Sacco, Antonio M. Persico, and Pat Levitt
Class V: Behavioral and Social Sciences
Insights on linking forests, trees, and people from the air, on the ground, and in the laboratory
Elinor Ostrom and Harini Nagendra
A PNAS Profile of Elinor Ostrom is available.
Class VI: Applied Biological, Agricultural, and Environmental Sciences
Maximilian Auffhammer, V. Ramanathan, and Jeffrey R. Vincent
A commentary accompanying this article is available.
2005 Cozzarelli Prize Recipient
Partition congruences and the Andrews-Garvan-Dyson crank
Karl Mahlburg
A commentary accompanying this article is available.

PNAS' first Paper of the Year prize was awarded to Karl Mahlburg, a doctoral candidate in mathematics at the University of Wisconsin, Madison, for his paper "Partition congruences and the Andrews-Garvan-Dyson crank." Mahlburg's article solves a critical part of a mathematical puzzle in number theory. His paper was chosen from among 3,000 papers published in the journal in 2005. Mahlburg was recognized on April 23, 2006, at the PNAS Editorial Board meeting in Washington, DC.
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